<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .k{
            width: 200px;
            height: 200px;
            margin: 300px;
            background-color: #f00;
            border-radius: 10px 20px 30px 40px;
            border-top-left-radius: 30px;
            /* 等同于
            border-top-left-radius
            border-top-right-radius
            border-bottom-right-radius
            border-bottom-left-radius
             */
            box-shadow: 0px 0px 0px 0px #000;
        }
        @media screen {
            box-shadow: none;
        }
    </style>
</head>
<body>
    <div class="k">

    </div>
</body>
</html>